SIST EN ISO 16784-2:2025
(Main)Corrosion of metals and alloys - Corrosion and fouling in industrial cooling water systems - Part 2: Evaluation of the performance of cooling water treatment programmes using a pilot-scale test rig (ISO 16784-2:2024)
Corrosion of metals and alloys - Corrosion and fouling in industrial cooling water systems - Part 2: Evaluation of the performance of cooling water treatment programmes using a pilot-scale test rig (ISO 16784-2:2024)
This document specifies the principles, reagents and materials, test apparatus, test methods, evaluation of results and requirements for test reports using pilot tests for industrial cooling water systems.
This document specifies a method to evaluate the performance of treatment programmes for open recirculating cooling water systems. It is based primarily on laboratory testing, but the heat exchanger testing facility can also be used for on-site evaluation. This document does not include heat exchangers with cooling water on the shell-side (i.e. external to the tubes).
Korrosion von Metallen und Legierungen - Korrosion und Fouling in industriellen Kühlwassersystemen - Teil 2: Bewertung der Leistung von Kühlwasser-Behandlungsprogrammen unter Anwendung eines Modell‑Prüfstands (ISO 16784-2:2024)
Dieses Dokument legt die Grundsätze, Reagenzien und Hilfsstoffe, die Prüfeinrichtung, Prüfverfahren, die Auswertung der Ergebnisse und die Anforderungen an die Prüfberichte mithilfe von Modell-Versuchen für industrielle Kühlwassersysteme fest.
Dieses Dokument legt ein Verfahren zur Bewertung der Leistung von Behandlungsprogrammen für offene Kühlwasserrezirkulationssysteme fest. Das Verfahren basiert primär auf Laborprüfungen, der Prüfstand, der einen Wärmetauscher simuliert, kann aber auch für eine Bewertung vor Ort verwendet werden. In diesem Dokument werden keine Wärmetauscher mit mantelseitigem Kühlwasser (d. h. Kühlwasser außerhalb der Rohre) erfasst.
Corrosion des métaux et alliages - Corrosion et entartrage des circuits de refroidissement à eau industriels - Partie 2: Évaluation des performances des programmes de traitement d'eau de refroidissement sur banc d'essai pilote (ISO 16784-2:2024)
Le présent document spécifie les principes, les réactifs et matériaux, l’appareillage d’essai, les méthodes d’essai, les méthodes d’évaluation des résultats et les exigences relatives aux rapports d’essai dans le cadre des essais pilotes des circuits de refroidissement à eau industriels.
Le présent document spécifie une méthode d’évaluation des performances des programmes de traitement destinés aux circuits de refroidissement à eau à recirculation ouverts. Elle repose principalement sur des essais en laboratoire, mais l’installation d’essai d’échangeur de chaleur peut également servir à une évaluation sur site. Le présent document ne traite pas des échangeurs de chaleur dans lesquels l’eau de refroidissement se trouve côté calandre (c’est-à-dire externe aux tubes).
Korozija kovin in zlitin - Korozija in obraščanje v industrijskih vodnih hladilnih sistemih - 2. del: Vrednotenje učinkovitosti programov obdelovanja s hladilno tekočino z uporabo opreme za preskuševališča pilotne serije (ISO 16784-2:2024)
Ta dokument določa načela, reagente in materiale, preskusno opremo, preskusne metode, vrednotenje rezultatov ter zahteve za poročila o preskusih z uporabo pilotnih preskusov za industrijske vodne hladilne sisteme.
Ta dokument določa metodo za vrednotenje učinkovitosti programov obdelovanja za odprte sisteme z recirkulacijo hladilne tekočine. Metoda temelji predvsem na laboratorijskem preskušanju, vendar je mogoče opremo za preskušanje izmenjevalnika toplote uporabljati tudi za vrednotenje na mestu uporabe. Ta dokument ne vključuje izmenjevalnikov toplote s hladilno tekočino na strani lupine (tj. zunaj cevi).
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2025
Korozija kovin in zlitin - Korozija in obraščanje v industrijskih vodnih hladilnih
sistemih - 2. del: Vrednotenje učinkovitosti programov obdelovanja s hladilno
tekočino z uporabo opreme za preskuševališča pilotne serije (ISO 16784-2:2024)
Corrosion of metals and alloys - Corrosion and fouling in industrial cooling water systems
- Part 2: Evaluation of the performance of cooling water treatment programmes using a
pilot-scale test rig (ISO 16784-2:2024)
Korrosion von Metallen und Legierungen - Korrosion und Fouling in industriellen
Kühlwassersystemen - Teil 2: Bewertung der Leistung von Kühlwasser-
Behandlungsprogrammen unter Anwendung eines Modell‑Prüfstands (ISO 16784-
2:2024)
Corrosion des métaux et alliages - Corrosion et entartrage des circuits de
refroidissement à eau industriels - Partie 2: Évaluation des performances des
programmes de traitement d'eau de refroidissement sur banc d'essai pilote (ISO 16784-
2:2024)
Ta slovenski standard je istoveten z: EN ISO 16784-2:2024
ICS:
77.060 Korozija kovin Corrosion of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 16784-2
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2024
EUROPÄISCHE NORM
ICS 77.060 Supersedes EN ISO 16784-2:2008
English Version
Corrosion of metals and alloys - Corrosion and fouling in
industrial cooling water systems - Part 2: Evaluation of the
performance of cooling water treatment programmes
using a pilot-scale test rig (ISO 16784-2:2024)
Corrosion des métaux et alliages - Corrosion et Korrosion von Metallen und Legierungen - Korrosion
encrassement des circuits de refroidissement à eau und Fouling in industriellen Kühlwassersystemen - Teil
industriels - Partie 2: Évaluation des performances des 2: Bewertung der Leistung von Kühlwasser-
programmes de traitement de l'eau de refroidissement Behandlungsprogrammen unter Anwendung eines
sur banc d'essai pilote (ISO 16784-2:2024) Modell-Prüfstands (ISO 16784-2:2024)
This European Standard was approved by CEN on 17 October 2024.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16784-2:2024 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 16784-2:2024) has been prepared by Technical Committee ISO/TC 156
"Corrosion of metals and alloys" in collaboration with Technical Committee CEN/TC 262 “Metallic and
other inorganic coatings, including for corrosion protection and corrosion testing of metals and alloys”
the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by June 2025, and conflicting national standards shall be
withdrawn at the latest by June 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 16784-2:2008.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 16784-2:2024 has been approved by CEN as EN ISO 16784-2:2024 without any
modification.
International
Standard
ISO 16784-2
Second edition
Corrosion of metals and alloys —
2024-12
Corrosion and fouling in industrial
cooling water systems —
Part 2:
Evaluation of the performance of
cooling water treatment programmes
using a pilot-scale test rig
Corrosion des métaux et alliages — Corrosion et encrassement
des circuits de refroidissement à eau industriels —
Partie 2: Évaluation des performances des programmes de
traitement de l'eau de refroidissement sur banc d'essai pilote
Reference number
ISO 16784-2:2024(en) © ISO 2024
ISO 16784-2:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 16784-2:2024(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Water for test . 3
5.1 General .3
5.2 Water characteristics .3
5.3 Preparation of synthetic test waters using mother solutions .4
6 Apparatus . 4
6.1 Heat exchanger section .4
6.2 Temperature measurement .5
6.3 Circulation-rate monitor . .5
6.4 Make-up, evaporation and blow-down measurement .5
6.5 Cooling tower .5
6.6 Heating system .5
6.7 Water treatment equipment simulation device .5
6.8 On-line detection device .6
7 Test method . 6
7.1 Procedure .6
7.1.1 Cleaning of the test assembly .6
7.1.2 Test tube preparation and pre-treatment .6
7.1.3 System water content .6
7.1.4 Procedure to fill the cooling water system .7
7.1.5 Heating the test tubes .7
7.1.6 Flow rate .7
7.1.7 Blow-down and half-life .8
7.1.8 Biocide treatment .8
7.1.9 Make-up water for cooling-tower use.8
7.2 Determination of analytical and control parameters .9
7.3 Test data reporting .9
7.4 Test termination .9
8 Assessment of results . 9
8.1 Recording of cooling water quality .9
8.2 Treatment of the test tubes .9
8.3 Assessment of results on deposition and fouling .9
8.4 Assessment of results on corrosion .10
8.4.1 Corrosion phenomena and type of corrosion .10
8.4.2 Pitting corrosion.10
8.4.3 Corrosion rate .10
9 Test report .11
Annex A (informative) Test data sheet on the performance of cooling water treatment
programmes .12
Annex B (informative) Further information on measurement and test methods .15
Bibliography .20
iii
ISO 16784-2:2024(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 262,
Metallic and other inorganic coatings, including for corrosion protection and corrosion testing of metals and
alloys, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 16784-2:2006), which has been technically
revised.
The main changes are as follows:
— the Introduction has been modified;
— the Scope has been modified;
— Normative references have been added;
— the Terms and definitions have been updated;
— Clause 4 has been modified to include principles on the simulation process of cooling water treatments;
— the title of Clause 5 has been changed from “Reagents and materials” to “Water for test”;
— the apparatus has been modified: the components and their descriptions have been added;
— the assessment of results has been modified to be divided into three aspects: corrosion phenomena and
type of corrosion, pitting corrosion and corrosion rate;
— the bibliography has been modified.
A list of all parts in the ISO 16784 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
ISO 16784-2:2024(en)
Introduction
There is an industrial need to improve the safety, reliability and cost-effectiveness of open recirculating
cooling water systems. This is due to the rise in stringent environmental requirements as well as the
rise in the costs of water. It is therefore important to establish a standard framework for evaluating the
performance of cooling water treatment programmes. The aim is to provide users of cooling systems and
vendors of treatment materials for those systems with a procedure to make consistent evaluations of cooling
water treatment programmes on a pilot scale.
With the continuous development of circulating water treatment technology, some new circulating water
treatment technologies, such as reverse osmosis treatment and electrochemical treatment, have become an
important part of cooling water treatment schemes.
This document has been revised and updated to add a new test device along with more detailed descriptions
of the components. The simulation device uses steam to heat the heat exchange tube, which solves the
problem of uneven heating caused by electric heating and is closer to the actual operating conditions on site.
v
International Standard ISO 16784-2:2024(en)
Corrosion of metals and alloys — Corrosion and fouling in
industrial cooling water systems —
Part 2:
Evaluation of the performance of cooling water treatment
programmes using a pilot-scale test rig
1 Scope
This document specifies the principles, reagents and materials, test apparatus, test methods, evaluation of
results and requirements for test reports using pilot tests for industrial cooling water systems.
This document specifies a method to evaluate the performance of treatment programmes for open
recirculating cooling water systems. It is based primarily on laboratory testing, but the heat exchanger
testing facility can also be used for on-site evaluation. This document does not include heat exchangers with
cooling water on the shell-side (i.e. external to the tubes).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 8044, Corrosion of Metals and Alloys — Basic Terms and Definitions
ISO 8407, Corrosion of metals and alloys — Removal of corrosion products from corrosion test specimens
ISO 16784-1, Industrial cooling water systems — Testing and performance — Part 1: Guidelines for conducting
pilot-scale evaluation of corrosion and fouling control additives for open recirculating cooling water systems
ISO 11463, Corrosion of metals and alloys — Guidelines for the evaluation of pitting corrosion
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
adenosine tri-phosphate
ATP
active chemical present in living bacteria
Note 1 to entry: ATP concentrations can be indirectly measured and are used as an indicator for the presence of
biology in cooling water.
ISO 16784-2:2024(en)
3.2
blow-down
discharge of water from the cooling water circuit expressed as a discharge rate
3.3
cooling tower
tower used for evaporative cooling of circulating cooling water, normally constructed of wood, plastic,
galvanized metal or ceramic material
3.4
cooling water treatment
adjustment of cooling water chemistry by which corrosion and fouling can be controlled
3.5
cycle of concentration
ratio of the concentration of specific ions in the circulating cooling water to the concentration of the same
ions in the make-up water
3.6
heat rejection capacity
amount of heat that can be rejected by a cooling-tower system
3.7
half-life
time needed to reduce the initial concentration of a non-degradable and/or non-precipitable compound to
50 % of its concentration in the cooling water
3.8
make-up water
total water mass per time unit, which is added to the system to compensate for the loss of water due to
evaporation, blow-down, leakage and drift loss
3.9
Reynolds number
LVρ
dimensionless form, , which is proportional to the ratio of inertial force to viscous force in a flow system
η
where:
L is the characteristic dimension of the flow system, expressed in m;
V is the linear velocity, expressed in m/s;
ρ is the fluid density, expressed in kg/m ;
η is the fluid viscosity, expressed in kg/m/s.
3.10
surface temperature
temperature of the interface between the cooling water film and the heat-transfer surface, whether the
surface is the tube wall or the outside of a fouling deposit
3.11
film fill
portion of a cooling tower, which constitutes its primary heat-transfer surface and over which water flows
as evaporation occurs
3.12
wall temperature
temperature sensed by a thermocouple placed between the heater element and the inside of the heat-transfer
tube wall, preferably as close to the tube wall as possible
ISO 16784-2:2024(en)
4 Principle
Model the circulating cooling water treatment process under specified experimental conditions. The metal
pipe samples are placed in circulating cooling water for heat exchange. Evaluate the performance of the
cooling water treatment scheme based on factors such as cooling water flow rate, water quality, material
flow intensity, heat transfer, the temperature of the cooling water inlet and outlet, concentration ratio, pH,
conductivity, concentration of water treatment additives and other critical technological parameters.
A test assembly of metallic test tubes is submitted under heat-transfer conditions to the circulation of
cooling water for a specified period. This can be connected directly to the cooling water system on-site, to
be representative of service conditions. For laboratory testing, the cooling water composition is designed to
reflect the chemistry for the service application but modified with the appropriate treatment programme
under investigation. The adoption of synthetic chemistry in laboratory tests can be effective for comparative
purposes, for example screening, but will not be representative of service conditions. The effect of the
cooling water circulation and the treatment programme on the corrosion and fouling of the test tubes is
assessed using a number of measurement parameters.
5 Water for test
5.1 General
The cooling water composition of the test should reflect the likely service application. For laboratory testing
using synthetic water, only reagents of recognized analytical grade and only water complying with the
minimum requirements of grade 3 of ISO 3696 shall be used.
There are two main operating environments. The first is to use the make-up water used in the specific
cooling system on-site (or to use synthetic make-up water) and concentrate it to the required number of
cycles in the test system. Annex A includes recommended forms for recording test conditions (see Table A.1,
Table A.2, Table A.3), compositions of make-up and recirculating water (see Table A.4) and test results (see
Table A.5, Table A.6, Table A.7). Annex B includes measurement and test methods.
The second approach involves using a synthetic water simulating on-site circulating water for the required
number of cycles. The use of synthetic circulating water obviates the need to concentrate the synthetic
water to obtain the desired cycles of concentration. This approach simplifies the test by avoiding the use of
the pilot cooling tower.
Synthetic circulating water usually contains a higher level of dissolved ionic solids than corresponding
natural water, thus making the synthetic water more corrosive.
5.2 Water characteristics
The natural or synthetic water(s) used should be characterized as specified in Table 1. Table 1 should be
used to record compositions of both the circulating water and the make-up water, if used. Turbidity, total
silica, bacteria and adenosine tri-phosphate (ATP) shall only be measured for on-site waters.
Table 1 — Composition of make-up and circulating cooling water
No. Component Value Units
1 pH, 25 °C pH units
2 Conductivity µS/cm
a
3 Total hardness
a
4 Alkalinity – p
a
5 Alkalinity – m
2+
6 Ca mg/l
2+
7 Mg mg/l
a
Depending on the test method, the unit of measurement is either mmol/L or mg/L.
ISO 16784-2:2024(en)
TTabablele 1 1 ((ccoonnttiinnueuedd))
No. Component Value Units
+
8 Na mg/l
+
9 K mg/l
+
10 NH mg/l
2+
11 Fe mg/l
2+
12 Cu mg/l
3+
13 Al mg/l
2-
14 CO mg/l
-
15 HCO mg/l
-
16 Cl mg/l
2-
17 SO mg/l
-
18 NO mg/l
3-
19 PO mg/l
20 SiO mg/l
21 Cl mg/l
22 Turbidity FTU or NTU
23 Suspended solids mg/l
24 Bacteria Cfu/ml or Cfu/l
25 ATP RLU
a
Depending on the test method, the unit of measurement is either mmol/L or mg/L.
5.3 Preparation of synthetic test waters using mother solutions
Synthetic test waters are normally prepared in the laboratory at the time of use by mixing mother or stock
solutions. One mother solution contains the alkalinity. The other stock solution contains the hardness and
other salts required in the test water. The composition of these two solutions is calculated so that, when
the solutions are mixed in the proper proportion, they prepare either the circulating test water or an
appropriate make-up water. Typical mother solutions are shown in Table B.1. Alternatively, mother solutions
can be prepared as concentrates and subsequently diluted with demineralised water.
6 Apparatus
6.1 Heat exchanger section
The core of the test assembly is the heat exchanger section, which is specified further in 6.2 to 6.7. The inner
wall of the heat exchange tube should have no pitting, crack, rust or other obvious defects. The length should
be determined according to the need. The test assembly comprises two or more metal heat-transfer tubes,
made of the relevant alloy used in the on-site heat exchanger. The heating mode can be steam heat exchange
(see Figure B.1) or electric, mounted either in series (see Figure B.2) or in parallel (see Figure B.3). Conduction
and convection of heat occurs through the heat-transfer tube wall into the circulating cooling water. The
materials of construction of the test assembly shall be chosen so as to not influence the composition of the
test water. Glass or plastic (e.g. polyvinyl chloride, chlorinated polyvinyl chloride or polyvinylidene fluoride)
is commonly used.
From the cooling water reservoir, the cooling water is pumped through the heat exchanger section at a
controlled flow rate. If the heat transfer tubes are mounted in series, only one flow rate controller is required.
If they are mounted in parallel, one flow rate controller is required for each heat exchange tube. Through
partial evaporation of water in a cooling tower (see 6.4), the heat absorbed is subsequently released to the
environment. Alternatively, if a cooling tower is not required to concentrate make-up water, a closed cooling
l
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